Electronic sound generators are often used for personal entertainment, recreation, relaxation and even to promote sleep. Users of such equipment find the sound of rain, falling water, wind, among other natural sounds, to be especially beneficial. The sounds may be used to mask out excessively loud and distracting ambient noise, to soothe the user, and even to help the user fall asleep.
Electronic sound generators usually can create several such sounds, and include a switch permitting user-selection of a particular sound. The generators also provide controls for volume and even to permit the user to modulate the effects of some of the sounds.
Some electronic sound generators output synthesized sounds. The nature or other sounds will first have been tape recorded, and a digitized representation of the recorded sounds are then electronically stored in a synthesizer integrated circuit ("IC"). The IC is then used in an electronic sound generator to output the user-selected synthesized stored sounds for listening.
Other electronic sound generators do not store sounds, but simulate sounds using white noise. Ideally, a "white noise" generator outputs a wide spectrum of frequencies, each frequency component being of equal amplitude. Sounds associated with running or rushing water, for example, may be readily simulated using a white noise generator. The amplitude of the white noise is often modulated, or changed, using a ramp signal. When the instantaneous magnitude of the ramp varies, the magnitude of the white noise sound will be varied. A control can permit the user to vary varying the rate at which the ramp changes amplitude to produce interesting sound effects from white noise electronic sound generators.
Whether generated from a single digital synthesizer IC, or from a single white noise source, electronic sound generators present the sound to left and right channel speakers or earphones. This can somewhat improve the sound quality perceived by the user, but nonetheless there is considerable room for improvement. The sounds often sound too "flat", with too little perception of sound depth or quality.
Also the somewhat limited repertoire of sounds available from most electronic sound generators can cause the user to become bored with the equipment. The sound patterns simply become too repetitious to be long enjoyed.
In some sound generators, variations in the sounds heard may occur too abruptly. Portions of an ocean wave sound, for example, may transition too abruptly from a quiet and calm wave sound to a loud rushing wave sound. The sensation can be a soft-loud-soft-loud repetitive pattern that is annoying to the user. In fact, some sound patterns that are too repetitively abrupt are believed to trigger seizures in epileptics.
In summation, there is a need for an electronic sound generator that can produce sounds having more perceived sound depth, and improved sensation of spatial separation between channels. Such generator should provide a greater variety of sound sensations, including the ability for the user to create new and continuously varying sound patterns.
The present invention discloses such an electronic sound generator.